electrical noise

[sb_89]

When testing recently a symbol on my megger mft came on, after looking through the legend, it was the electronic noise symbol. I know it's caused by electrical equipment i.e motors. my question is, does it have any affect on the installation. All it says in the megger book is that more investigation is required and I can't find anything else about it any where. My fluke doesn't show it at all. Anyone know anything about it ?

 

[Badger]

i could be down to the connections on the probes if they wernt very good and jumpy ie touching then not touching then touching that could cause noise as ive had the same with my rcd tester when the connection isnt as good first time round

 

[sb_89]

No, I carried out the test at least 5-6 times. I took the readings from the fluke in the end, I was just wondering if electronic noise actually has any effect on anything ? Is it frequency related?

 

[batty]

I honestly don't think Megger have got the low current loop testing right reading a few other posts in the past. As said before I have a cm500 which constantly would display this and the readings where always way out. I will stick with my Fluke.

 

[apprentice87]

Hi All,

Well, my megger works great!!

Anyway, electrical noise; What sort of installation was it?? If it is not generated within the installation itself, i would be straight on to the DNO.

I think it it not so much motors that cause noise, but VFD,s and other electronic stuff, that sort of thing. I cannot see that ordinary switching would do much, unless there was LOADS of it going on.

Electrical noise can cause problems with lots of stuff, computers [Good!!] but also electronic equipment in general, motors, transformers and anything electrical i suppose, you see the "proper" smooth sine wave that you should have, ends up all spiky and stuff. I would not be happy at all.....

I would DEFINITELY be on to the DNO. They will be well interested, and when they find whoever is causing it, they will disconnect them i expect....

Here is what the ESQCR regs have to say on the issue...

"Where a connection to a distributor

 

[sb_89]

That's really helpful John, thank you. it's a 3 phase tns system. It's a modern installation - 5 yrs. There are a few air handling units and other pieces of large 3ph&n commercial equipment. At the main section board there is surge protection . The building is a Community centre / daycare centre

It's very difficult to say if it's our end or the DNO end as its not very practical to turn the supply off unfortunately. Further investigation required I guess !

Thanks John , if I can't figure out what is causing it I shall inform the DNO

 

[apprentice87]

Hi Sb89,

I know the sort of thing that goes on in daycare centres, and so i very much doubt that it is "home grown" noise... All you will have is a few ordinary computers and some commercial cookers and that sort of thing, nothing out of the ordinary!!!

I would definitely contact the DNO.... Is there a nearby industrial estate or industrial units?? Someone has got a load of them variable frequency things connected up i would think..

I have a Megger 1730 and i have used that in industrial settings, with motors running and electric cranes and stuff all operating, and computers and all sorts, but i have never had the warning about noise come up.

I wonder if all these solar panels that pop up everywhere generate noise??? I would not be surprised if they did, because how do they synchronise the frequency with the "proper" supply?? presumably with a load of made in china el-cheapo electronic gubbins. Would not be surprised if they do funny things..Are there any of these nearby???

I know that the DNO here have a program of installing voltage monitor things in peoples premises going on at the moment, to, as they put it, "make the LV network visible"

It is because as there are all these stupid solar panels everywhere now, the poor old DNO have no idea of exactly what is arriving at consumers premises, as they now have no control over what is "input" into their network, nor any control one suspects, of the quality of this "input"

I know nothing of solar panels and the like, but i would not be surprised if they are at the root of it all.......

Contact the DNO, as they have to deliver you a clean supply by law, and they will come down really hard on anyone introducing "interference" to their beloved system.

It would be a bit like how you would feel if you had no control over the quality of the petrol that went in your car, and people kept coming along in the night and filling your tank with thinners, or meths or something!!!!!!

john..